Standard head distance on a 5'7" male is about 11.5" from the shoulders to the top of the head.

So that is about 17%. So on a 6'9" male the proportional distance would be about 20% more or almost 14". It appears in the picture that Nash's head comes up to about AJ's mouth, which is less than half the distance between AJ's shoulder's and the top of his head. Nash is 6'3", therefore AJ must be at least 6'10" assuming each has the same soul height on their footwear.

When considering the heights of AJ and Nash, one must also consider the fact that Nash is standing in front of AJ. This proximity makes his head look larger. Also, Nash is only reaching the heights of the troposphere, while AJ's height puts him up into the stratosphere. Also consider wind velocity at the different heights............

When considering the heights of AJ and Nash, one must also consider the fact that Nash is standing in front of AJ. This proximity makes his head look larger. Also, Nash is only reaching the heights of the troposphere, while AJ's height puts him up into the stratosphere. Also consider wind velocity at the different heights............

Click to expand...

All of those considerations, offset one another for a net difference of zero.

I noticed one thing in that first photo that was encouraging. If you look closely at AJ's pants you will see that they are "high water" pants meaning that he has probably gone through a recent growth spurt.